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Processes for preparing of 3,4-alkylenedioxythiophenes and 3,4-dialkoxythiophenes

a technology of alkylenedioxythiophene and process, which is applied in the field of process for preparing 3, 4dialkoxythiophene and 3, 4alkylenedioxythiophene, can solve the problems of environmental pollution, impurities such as tar-like materials, and drawbacks on an industrial scale, and achieves the effect of simple and easy preparation

Inactive Publication Date: 2007-04-10
BAIK WOON PHIL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

"The present invention provides a simple and easy process for preparing 3,4-dialkoxythiophenes and 3,4-alkylenedioxythiophenes by decarboxylation of their corresponding acid in a water-miscible polar solvent with a lower boiling point than the final product, in the presence of copper catalyst under an oxygen atmosphere. The process can be carried out at low temperature in a short reaction time to prevent the formation of a tar-like byproduct. The invention is particularly suitable for preparing 3,4-ethylenedioxythiophene and alkyl-substituted compounds."

Problems solved by technology

1) The boiling point of quinoline is 238° C., while the boiling point of the final product (EDOT) is 225° C., and thus the product can not be isolated by fractional distillation. Instead, it must be isolated or purified by column chromatography, which is a drawback on an industrial scale.
2) The solvent quinoline should be avoided since it interferes with the workup process. Workup is carried out by washing with water and acid. The quinoline salt enters the waste-water, where it then causes environmental pollution or adds an additional step to recover the quinoline salt from the aqueous phase.
3) Since the reaction is carried out at high temperature (not lower than 180° C.) for a long period of time, substantial impurities such as tar-like materials are formed to give a bad yield (60% or less) or difficulties in purification.
This reaction is inappropriate for an industrial scale because it requires a considerable expenditure of energy and special equipment.
According to this process, decarboxylation is performed without catalyst by heating at 240° C. or higher for 24 hours, or in the presence of high-boiling-solvent and copper salt catalyst at 140° C. for 8 hours or more, and, similar to the prior arts it also gives a tar-like byproduct that impedes purification and reduces the yield.
Thus, this process is complicated and gives low productivity.

Method used

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  • Processes for preparing of 3,4-alkylenedioxythiophenes and 3,4-dialkoxythiophenes
  • Processes for preparing of 3,4-alkylenedioxythiophenes and 3,4-dialkoxythiophenes
  • Processes for preparing of 3,4-alkylenedioxythiophenes and 3,4-dialkoxythiophenes

Examples

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Effect test

example 1

Preparation of EDOT in DMSO in the Presence of a Copper Powder Under Oxygen

[0032]3,4-Ethylenedioxythiophene-2,5-dicarboxylic acid (460 g) and a copper powder (46 g) were added to DMSO (1200 g) at room temperature. The reaction mixture was stirred under an oxygen atmosphere for 30 minutes at room temperature and then heated at 120° C. for 6 hours. The reaction mixture was then poured into ice water (1200 mL), and the crude product was extracted with ethyl acetate. After drying over anhydrous sodium sulfate, the solvent was removed by evaporation. The residue was vacuum-distilled at 30 mmHg to give 283 g of 3,4-ethylenedioxythiophene at high purity (99.7% or higher). The purity was confirmed by gas chromatographic analysis (compared to decane as an internal standard). The chemical structure was confirmed by mass analysis and 1H-NMR.

example 2

Preparation of EDOT in Ethylene Glycol in the Presence of a Copper Powder Under Air

[0034]3,4-Ethylenedioxy-2,5-thiophenedicarboxylic acid (460 g) and a copper powder (69 g) were added to ethylene glycol (1400 g) at room temperature. The reaction mixture was stirred under air for 30 minutes at room temperature, and air was continuously introduced into the reaction mixture. The reaction mixture was then heated at 140° C. for 8 hours. After the reaction was complete, the reaction mixture was purified using the same process as described in Example 1 to obtain 3,4-ethylenedioxythiophene (281 g, purity: 98%).

example 3

Preparation of EDOT in DMF in the Presence of Basic Copper Carbonate Under Air

[0035]3,4-Ethylenedioxythiophene-2,5-dicarboxylic acid (230 g) and basic copper carbonate (23 g) were added to DMF (600 g) at room temperature. While air was slowly introduced to the reaction mixture, it as heated at 120° C. for 5 hours. After cooling, the reaction mixture was purified using the same process as described in Example 1 to obtain 3,4-ethylenedioxythiophene (136 g, purity: 97%).

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Abstract

The present invention relates to a process for preparing 3,4-dialkoxythiophenes or 3,4-alkylenedioxythiophenes in high yield via the rapid decarboxylation of 3,4-dialkoxythiophenedicarboxylic acid or 3,4-aklylenedioxythiophenedicarboxylic acid in a water-miscible polar solvent in the presence of copper catalyst under an oxygen atmosphere.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a process for preparing of 3,4-dialkoxythiophenes and 3,4-alkylenedioxythiophenes. More specifically, it relates to a process for preparing of 3,4-dialkoxythiophenes and 3,4-alkylenedioxythiophenes in high purity by the decarboxylation of 3,4-dialkoxythiophenedicarboxylic acid and 3,4-alkylenedioxythiophenedicarboxylic acid, respectively, in a water-miscible polar solvent in the presence of copper catalyst under an oxygen atmosphere.BACKGROUND OF THE INVENTION[0002]This invention relates to a process for preparing of 3,4-dialkoxythiophenes and 3,4-alkylenedioxythiophenes by the decarboxylation of 3,4-dialkoxythiophenedicarboxylic acid and 3,4-alkylenedioxythiophenedicarboxylic acid, respectively, in a water-miscible polar solvent in the presence of copper catalyst under an oxygen atmosphere. As conductive polymers, polyanilines, polypyrroles and polythiophenes are used in various applications of electronic materials. In pa...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): C07D495/02C07D333/00C07D495/04H05K3/18
CPCC07D495/04H05K3/188
Inventor BAIK, WOON-PHILKIM, YOUNG-SAMHONG, HEE-JUNGJUNG, SANG-GOOK
Owner BAIK WOON PHIL
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